Method and device for the increase of floating stability of airplanes



March 1 1927.

A. ROHRBACH METHOD AND DEVICE FOR THE INCREASE 0F FLOATING STABILITY OF AIRPLANES Filed July 14, 1924 meme! Mar. 1, 1927.

UNITED STATES PATENT OFFICE, v

ADOLF nonnnncr'i, or nnnnm-wxnmnnsnonr, GERMANY.

un'rnon Aim DEVICE- iron man mcnnnsn or FLOATING STABILITY or IRPLANE-s.

Application fi led July 14,1924, Serial lio. 725,833, and in Germany July 25, 1923.

This invention relates to airplanes and the] object of the invention generally is a method and means for rendering an airplane stable and more tranquil while standing or floating in exposed places.

In the design of airplanes the wings or lifting'surfaces are so designed as to give,

a good lift at a certain relative speed of the craft and the air, but such lifting character 1o istic, which is essential for eflicient flying, is

a particular disadvantage while the craft is standing or floating in exposed spacesfdue tothe lifting and disturbing eflects .of the gusts of wind upon the lifting surfaces which cause the craft to rise and 'fall with resultant jars and poundin craft,a quiet standing and oating being thereby rendered impossible. This disadvantage is particularly noticeable in and injurious to moored seaplanes which, when more violent gusts occur are often lifted or partially lifted like kites and dropped backwith the abatement of the wind gusts with pronounced force to the water surface. The machines are greatly endangered by such jars or pounding and are frequently damaged and often wrecked. Prior to my in vention it had been practically impossible to moor seaplanes with safety to the craft in exposed places subject to stron winds.

According to my invention 't ese difliculties are obviated and according thereto I utilize a method and suitable devices for reducing or destroying the harmful disturbing and lifting efli'ect ofthe air currents upon N the liftin surfaces while the craft is standing or places,-the heretofore harmful air currents or gusts themselves being utilized through these novel instrumentalities to effect the.

stabilizing and quieting function.

For a better understanding of the invention, reference may be had to the accompanying drawings including illustrations of several embodiments of the invention,

wherein: A

Fig. 1 shows in side elevation the wing part of a bi-plane with an additional area of resistance. I0 Fig.2 shows a section of a, bi-plane with changeable wing profile. H

Fig. 3 is the wing of a monoplane with an additional areasof resistance. Fig. 4 shows the wing of a m'onoplane with changeable profile.

' Fig. 5 is the wing of a monoplane with of resistance.

upon the oating in the open or exposed 3' changeable pr ofile and an additional area the wing of a monoplane with changeable profile.

Figure 7""shows a view. in perspective of a-wing embodying one form of my -inventlOIl.

In accordance with Fig. 1 an auxiliary plane 5 is spread out between the supporting planes 3 and 4 of a bi-plane, within'the space between the front struts l and the rea struts 2.

The incoming gust of wind attacking the additional plane divides into two components, of which the one, acting downwards, counteracts the lifting component and, with equal magnitude, neutralizes it, so that the aircraft is not able to rise above the surface of the water. By making the height of the suspension point 6 adjustable, the size of the additional area of resistance .and consequent 1y its effect can be modified. The resistance of the wing isnaturally enhanced to a certain extent by the auxiliary area, but that is not essential as long as the craft is rlding at anchor.

.down, so that they can be set up against the wind when the machine floats on the water.

It is not advisable to have these flapsextend as a whole, throughout the entire span, for

the reason that, if subdivided, larger or' smaller parts may be set up against the wind, just as may be required.-

Fig. 3 shows the wing of a monoplane, the lifting force of which is eliminated by the putting up of a wind-screen-area 1 which may consist of more or les s r1g1d plates or, a canvas strip, held in position at its top edge by means of a rope or bar. This wind catching plane 10 is braced against the wing by struts or cables 11, 12.

Fig: 4 shows a modification of Fig. 3, in which the employment of an independent wind-catching plane has become unnecessary, and part of the outer skin of thewmg is taking its place. Within the wing 9, m

which the spars or the like 13 and '14 are provided, a joint-strut arrangement 15, 16 has been fitted, the latter serving the purpose to open the skin of the floating machine Fig. 5 illustrates a cut through the wing 9, in which for the decrease of the lifting force on the water the nose part 18 of the wing can pivot downwards round an axis 19. This nose part of the wing is held in its turned position by struts or the like 20. The struts may be constructed as a more or less rigid surface, and besides, they may also be fitted with a plane of resistance 21,. ex tending throughout the larger part of the span, which arrangement would cause a further reducement of the lifting force.

Fig. 6 shows another modification in which the nose-box 18 is constructed in such a manner that, formed in its elongation by the outer skin plate 22, it extends rearwards to I the rear part 9 of the wing. During the machines floating on the water the nose part is turned downwards, and the skin plate 22 serves then as a plane of resistance, while (luring flight, it is laid flat against the back of the outer skin of the wing 23.

It is advisable to select for any airplane a type of wing-transformation enabling the crew to effect by themselves all necessary changes and ad ust-ments. Therefore it is always of advantage to have these individual parts not extending as a whole throughout the span, but rather have them divided into several separate parts, arranged in series.

The invention, although of particular importance for seaplanes, may also be employed with landplanes in order to prevent an overturning of the machine by squalls, etc., while standing on the flying ground.

Claims.

1. An airplane including a lift reducing device associated with the main lifting wing area thereof and sufficiently co-extensive with the span of the craft to neutralize or reduce the lifting force of wind gusts thereon to a harmless degree while the craft is stand ing in exposed places, said lift reducing de vice bein independent of and separate from but readily attachable to the craft while standing.

2. An airplane of the character set forth in claim 1 wherein the lift reducing or neutralizing devices comprise means for substantially impairing the lift characteristic of the main lifting surfaces throughout a substantial portion of their span.

3. An airplane of the character set forth in claim 1 wherein the lift reducing or neutralizing'device comprises auxiliary negative lift and resistant surfaces which exert a depressing influence on the craft contrary to" 4. An airplane of the character set forth in claim 1 wherein the lift reducing device consists of a multiplicity of separate and distinct parts which are associated with the main lift surface area and are individually adjustable for reducing the net lifting effect of wind gusts upon the main lift surface area to the exact degree desired.

5.-An airplane including auxiliary connections disposed throughout a substantial portion of the span whereby suitable lift reducing devices may be readily attached thereto and adjusted with reference to the main lifting surface area to reduce to a harmless value the lifting effect of wind gusts thereupon while the craft is standing in exposed places.

6. The combination of an airplane of he multi-plane type with a resistance device fitted between two of the planes and extend ing throughout the greater portion of the length thereof for blocking the gap therebetween and reducing the lifting or disturbing effect of air gusts thereupon to a harmless degree while the craft is standing in exposed 4 places.

7. An airplane whose main lifting surfaces have a part thereof extending throughout a substantial portion of the span which normally forms a fixed and unalterable part thereof during flight but is capable of being turned or operated out of its operative flight position while the craft is standing or floating in exposed places in a manner to change the profile from an efficient lift characteristic to one of substantially no lift and to reduce the aerodynamic lift thereof to a harmless degree whereby the normal tendency of the craft to be lifted from its resting position is avoided.

8. An airplane whose main supporting wing area may be readily changed from an eflicient lift profile to a profile of substantially no lift and including a resistance or neutralizing surface associated with the main wing area and cooperating with the change in profile to reduce to a' minimum the lift ing or disturbing "effect of air gusts upon the wing area while the craft is standing in exposed places.

9. An airplane of the character set forth in claim 7 wherein the normally fixed but specially alterable part of thelifting surface consists of a transverse pivotal edge "thereof which can be turned at right angleslo' the fore and aft direction.

Dated this 2nd day of July, 1924.

DR. ADOLF ROHRBACH. 

